As more people build homes in fire-prone areas of the West, the cost of fighting fires has more than tripled – and taxpayers who live far from the front lines are helping to foot the bill.

Climate change, dry weather, and past forest management practices have created conditions where forests spark quickly and burn long. But much of the increased cost comes from protecting large communities on vulnerable land that used to be free of people. There are now more than 47 million homes in areas at high risk for wildfires, according to a study conducted by the U.S. Forest Service and several universities, with nearly 10 million sprouting in so-called “wildland-urban interface” areas between 2000 and 2010 alone.

“We have way more houses to protect, and that’s a costly proposition,” said Volker Radeloff, a professor at the University of Wisconsin who helped prepare the study. “The question becomes, how much should society at large pay for their loss?”

Radeloff called the cost of firefighting “largely, but not entirely, a federal cost.” Up to two-thirds of the cost of fighting wildfires in the U.S. comes out of the federal budget. Together, the U.S. Forest Service and Department of the Interior now spend an average of $3.5 billion a year to fight fires, three times what they spent annually in the 1990s, according to a 2013 report from the Congressional Research Service.

Fire management assistance grants from the Federal Emergency Management Agency have also tripled since the 1990s. They averaged $71.2 million a year between 2002 and 2011, according to a recent report on wildfires from Headwater Economics, a non-profit that studies Western development.

The cost to insurers has grown even faster. Annual economic losses from wildfires have averaged $1.3 billion since 2000, according to data from the risk management and insurance group Munich Re, almost five times the annual average of $286 million in the 1980s.

As for what this fire season might mean for insurance rates going forward, “It’s too early to say,” said Michael Barry, vice president of media relations at the Insurance Information Institute, an industry-funded consumer education group.

The $1.1 billion in losses wrought by wildfires last year is dwarfed by the nearly $19 billion from Hurricane Sandy. Fire remains a lower priority for insurers than natural disasters like hurricanes, tornadoes and floods.

“While wildfires are definitely a concern," said Barry, "they generally do not generate the insured losses that insurers see after major hurricanes or tornadoes."

And so far, 2013 has been a somewhat tamer year for wildfires than many before it. While the nation’s firefighting resources are currently stretched to the limit, according to the National Interagency Coordination Center, which coordinates local, regional and national firefighting agencies, the overall figures are down. There have been 33,000 fires so far in 2013, burning just under 3.3 million acres, according to NICC data, some 2 million acres below the 10-year average.

But as more people look to live with the national forest as their backyard, costs will likely remain high even in those years when fire is more controlled. The pace of building may even have picked up -- the 10 million homes added in risky areas over the last decade followed an addition of 6 million homes in the 1990s.

“The growth in the wildlife-urban interface doesn’t seem to be slowing down, and that means that the problem is going to be with us for the foreseeable future,” said J. Keith Gilless, dean of the College of Natural Resources at U.C. Berkeley and chairman of the California Board of Forestry and Fire Protection. Gilless said communities should take measures to protect land -- clearing vegetation, creating good infrastructure and educating homeowners. “You can do this in a more intelligent or a less intelligent way,” he said.

“The fires are bigger, they’re burning longer, the season is longer, and then we have climate change,” said Ray Rasker, executive director of Headwater Economics. “Those we can’t do much about in the short term. But what we can change is where we build homes. That can control the number of homes that are burnt, the firefighter lives at risk, and in particular the cost of fighting these fires.”

Several federal watchdogs have encouraged what they say is a smarter way to manage costs. While the federal government spends $3 billion a year fighting fires, local and state governments spend $1 billion to $2 billion. Shifting some of the growing federal fire suppression costs to them would also mean shifting costs to taxpayers who live in the danger zones – and might inspire local governments to slow growth in high-risk areas.

A 2009 report from the Government Accountability Office said because the federal government shoulders the cost of much wildfire fighting, state and local governments have little incentive to put in place policies, like stricter building and zoning rules, that would help cut the costs of battling the flames.

“We need more responsibility at the local level,” said Rasker. “Right now the firefighting costs are borne by the federal taxpayer. That’s the crux of the problem here. Until it affects somebody’s budget, we’re not going to see much change.”